UC Irvine

Seaweed farming comprises over half of global coastal and marine aquaculture production by mass; however, the future of the industry is increasingly threatened by disease outbreaks. Nature-based solutions provided by enhancing functions of coinciding species or ecosystems offer an opportunity to increase yields by reducing disease outbreaks while conserving biodiversity. Seagrass ecosystems can reduce the abundance of marine bacterial pathogens, although it remains unknown whether this service can extend to reducing disease risk in a marine resource. Using a meta-analysis of articles published over the past 40 y, we find that 17 known diseases of seaweeds are attributed to bacteria that have been previously shown to be lower when associated with seagrass ecosystems. Next, we surveyed over 8,000 individual seaweeds among farms in Indonesia and found that disease risk is reduced by 75% when seaweeds are co-cultivated directly within seagrass ecosystems, compared to when seagrass ecosystems were removed. Finally, we estimate that farming seaweed with seagrass ecosystems could increase annual revenue by $292,470 - $1,015,990 USD per km2 from yield loss due to disease reduction and that ~20.7 million km2 in 107 countries and 34 territories have suitable environmental conditions for farming seaweeds with seagrass ecosystems. These results highlight the global utility for nature-based solutions as an ecologically and economically sustainable management strategy.